Cooling device in multistage centrifugal compressors



' 2B. GRAEMIGER I COOLING DEVICE IN MULTIS TAGE CENTRIFUGALCOMPRESSORS. v

APPLICATIONHLED 05C. 1.1920.

1,425, 55, Patented Aug. 15, 1922.

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-UNHTE I BENJAMIN G-RAEMIGER, or sun-Ion swrrznnnaun.

COOLING DEVICE IN MULTISTAGF- 'cnnrairusan coMrnnsson-s.

T 0 all whom it may concern: v

Be it known that I, BENJAMIN Gum-iris in, a citizen of the Republic of Switzerland, residing at Zurich, Hardturmstrasse v19, Switzerland, have invented certain new and use ful Improvements in Cooling Devices in Multistage Centrifugal Compressors; and I do hereby declare the following to be a clear, full, and exact description of the invention, such as will enable others skilled in the art to which it appertainsto make and use the same, reference being had to the accompanying drawing, and to letters or figures of reference marked thereon, which form a partof this specification.

This invention relates to a cooling device in multistage centrifugal compressors having cooling channels parallel to the, axis of the compressor shaft.

Cooling devices of this type form the subject matter of my Patent No. 1265650 dated May 7 1918. The object of the present invention is a further improvement on the cooling devices described and claimed in said patent. 1

According to the invention some of the stages are arranged within the range of the cooling channels which are parallel to theaxis of the compressor shaft and only the remaining stages alternating with the first mentioned stages are passed by the cooling channels.

One mode of carryingthe invention into effect is shown by way of. example in the accompanying drawing. This drawing illus trates part of a longitudinal section through an air-compressor having eight stages. The

path of the air on its way through the compressor is indicated by arrows shown in dotted lines. The rotor wheels 1, 3, 4 and 6 deliver the air into diffusers which open to- .ward the circulation chambers 9,10, 11 and 13 respectively. The latter are arranged within the range of the cooling tubes 14, 15, and 16. The rotor wheel 2 delivers the air compressed by the latter into a circulation space 17, the rotor wheel 5 delivers the" air through an interposed diffuser into the circulation chamber 18 and the rotor wheel 7 through a diffuser into the circulation space Specification e2? Letters Intent. Pggiggniiegfi Application filed December 1, 1920. serial no. 427,564;

ring, is, 1922;

rangement presents the advantagethat the cooling tubes 1a 15, 16 have only to pass" through four cast. partition walls 21, 22, 23 and 24, i. e. in the number of partition walls separating the pressurestages through which the tubes have to passyis equalto only half th number of the stagesof a compressor. Thereby, whilst maintaining the total eifec tive area of the cooling surface, the construc tion of a compressor is rendered much simpler, lighter and cheaper than if all the partition walls separating the single stages were to be extended up to the outer wall27 of the compressor casing andif every cooling chan nel had to pass through all these many partition walls.

Further, the construction according to the invention is particularly advantageous in case a compressor has tobe designed to be driven by a prime mover that runs at a comparatively low speed. Owing to the small circumferential speeds, a large number of stages has to be provided and it is not necessary to cool each stage. This may even prove disadvantageous, owlng to the-drop of pressure caused by cooling each stage. If

the me'dium'is compressed in two or more successive stages without being cooled and the cooling is then applied in a subsequent stage the temperature difference between the compressed medium and the cooling means of the pressure-stages of the compressor, and

the remaining pressure-stages so arranged that they are not intersected by said coollng channels.

, 2. In a multistage centrifugal compressor, 1 acoollng device comprising cooling channels arranged substantially parallel to the axis of the compressor, and half of the number of partition walls separating the single stages extending to the outer wall of the compressor casing and being passed by said cooling channels. a l 3.. In multistage centrifugal compressor; a cooling device comprising cooling channels former chambers and cooling means for said other chambers.

5, A multistage centrifugal compresson, comprising some of the successiv stages con nected by circulating chambers, and other.

circulating chambers connecting other successive stages, said other chambers extending radially beyond the former chambers and laterally thereover, and cooling means for said other chambers.

In testimony that I claim the foregoing as my invention, Ihave signed my name.

BENJAMIN GRAEMIGER. 

